Restarts, BlueScreens, Crashes... omg

Hi guys... while im uding 3d aplications like nba live 2005 and 04 my pc crashes, ramdomly restarts and most of the time gives me a blue screen with a msg IRQL_NOT_LESS_OR_EQUAL..

I tried to install different drivers from nvidia, 3dguru and omegadrivers but still theres no difference...

I tried to remove my current memory(geil dual memory 256mb 2X) and replaced it with an old memory stick (256MB) and it worked fine... but i also tried to use my memory(geil dual memory 256mb 2X) individually and worked fine... my mobo supports dual memory channel (asus A7V880)... Any suggestions might help..
sorry for my poor english...

P.S. Its running smoothly when im playing mp3 with my geil memory 2x...